The one page brief
Keep it to a single page with five parts. Who the product is for, the one thing to land, what they must avoid saying, the call to action and the delivery date. Add three example posts of theirs you liked so the reference is their own work.
Anything longer gets skimmed. A twelve page deck with brand values, tone of voice pillars and a mood board produces cautious, generic content because the creator is trying to avoid getting it wrong instead of trying to make it good.
What you should control
Legal and factual accuracy, always. Health claims, price claims, comparative claims and anything regulated in your category. Give the creator a short list of approved phrases and a short list of banned ones. That is a guardrail they can work inside.
Also control the practical details. Correct product name and spelling, the offer, the code, the link and the disclosure. Those are the things that actually break campaigns. They take one line each to specify in the brief.
Handle approvals like a professional
One round of feedback, factual corrections only, returned within 48 hours. Say that in the contract. Endless subjective rounds are the main reason good creators stop working with brands. Each round pushes the content further towards a television advert.
If you genuinely dislike a piece of content, pay for it, do not post it and cast better next time. Rewriting a creator’s script produces something the audience can smell instantly. The numbers usually show it within a day of posting.